(19)
(11) EP 1 832 666 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
12.12.2007 Bulletin 2007/50

(43) Date of publication A2:
12.09.2007 Bulletin 2007/37

(21) Application number: 07011572.0

(22) Date of filing: 20.01.2004
(51) International Patent Classification (IPC): 
C22C 38/00(2006.01)
C22C 38/58(2006.01)
 C22C 38/12(2006.01)
(84) Designated Contracting States:
DE FR GB

(30) Priority: 20.02.2003 JP 2003042398

(62) Application number of the earlier application in accordance with Art. 76 EPC:
04703503.5 / 1598437

(71) Applicant: Nippon Steel Corporation
Tokyo 100-8071 (JP)

(72) Inventors:
  • Yamasaki, Shingo
    Kimitsu-shi Chiba 299-1141 (JP)
  • Hirakami, Daisuke
    Futtsu-shi Chiba 293-8511 (JP)
  • Tarui, Toshimi
    Futtsu-shi Chiba 293-8511 (JP)
  • Nishida, Seiki
    Kimitsu-shi Chiba 299-1141 (JP)

(74) Representative: Vossius & Partner 
Siebertstrasse 4
81675 München
81675 München (DE)

   


(54) High-strength steel material with excellent hydrogen embrittlement resistance


(57) The invention provides a steel material with satisfactory hydrogen embrittlement resistance, and particularly it relates to high-strength steel with satisfactory hydrogen embrittlement resistance and a strength of 1200 MPa or greater, as well as a process for production thereof. At least one simple or compound deposit of oxides, carbides or nitrides as hydrogen trap sites which trap hydrogen with a specific trap energy is added to steel, where the mean sizes, number densities, and length-to-thickness ratios (aspect ratio) are in specific ranges. By applying the specific steel components and production process it is possible to obtain high-strength steel with excellent hydrogen embrittlement resistance.







Search report